We have witnessed this happen with regularity, and it is a customer who signed a cost-per-print contract where they ran out of toner. Especially if you need it immediately, you do yourself a disservice if you have not come prepared.
Keeping a spare set of toner and other supplies on the shelf avoids this issue. Even the best copiers will not work 100 percent of the time, and if you have a part on back order, it makes copying impossible for a couple days. While we do keep loaner devices for our local clients, it may also be easier if you have a $200 back up unit on-site.
To avoid experiencing issues, we recommend checking toner levels, and you want to make sure that the person in charge of your copier understands how to order supplies and services. We advise our customers use the software to place service calls rather than calling HP, or us. You will find that it is much faster because the software will skip the wait and place your ticket at the front of the queue. Here in Chicago, we want our customers to feel happy with the services they received. Monitor your toner levels closely to ensure that you will never run out when you need it most.